1. In the Parliamentary form of government, there are two heads. One is a nominal head while another is the real head. For example, in India, the President is the nominal head while the Prime Minister is the real head. The President of India is the head of state while the Prime Minister is the head of government. But in the Presidential form of government, there is only one head. The President of America is the head of state as well as the head of government.
2. In the Parliamentary system, the Council of Ministers headed by the Prime Minister is responsible to the legislature. But in the Presidential type, the President and his ministers are not responsible to the legislature.
3. In the Parliamentary type, the Council of Ministers will lose office if it loses the vote of confidence / no confidence. But in the Presidential type, the President cannot be ousted from power by a vote of no-confidence. He can be removed from office though impeachment which is much more difficult than the vote of confidence/no confidence.
4. In the Parliamentary system, the government does not enjoy a fixed tenure."For example, in India the government can stay in power for five years. But any time during this period, the government can be removed from power through a vote of no-confidence. In the Presidential system, the President has generally a fixed tenure because it is not easy to impeach him.
5. There is not strict separation of powers in the Parliamentary type. The ministers are also members of the legislature. But, in the Presidential type, the principle of separation of powers is strictly followed. In the US, the President and his Ministers (Secretaries) are not members of the Congress.
6. In the Parliamentary system, the Prime Minister is not fully free to choose his ministers. He has to choose them from among the members of Parliament. But in the Presidential system, the President enjoys much more freedom in selecting his ministers. He selects them from a much wider field taking into account their experience and expertise.
7. At the time of crisis the Presidential executive is more successful in taking prompt and bold decisions than the Parliamentary government.
8. The Presidential system of government provides more political stability than the Parliamentary form of government.
9. As the government in the parliamentary system is responsible to the Parliament, it is more democratic and respectful of public opinion than the Presidential executive which is not responsible to the legislature.